1. Field of the Invention
The present invention relates to an antistatic optical film comprising an antistatic layer laminated on at least one side of an optical film, and a method for manufacturing the same. Furthermore, it relates to an image viewing display using the above-mentioned antistatic optical film, such as liquid crystal displays (LCDs), organic electroluminescence viewing displays, and PDPs. As the optical films, a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, etc., and furthermore optical films with the films laminated to each other may be mentioned.
2. Description of the Related Art
In liquid crystal displays etc., an image forming system necessarily requires polarizing elements disposed on both sides of a liquid crystal cell, and in general, polarizing plates are adhered thereto. Moreover, in liquid crystal panels, in order to improve display quality of displays, various optical elements in addition to the polarizing plates are increasingly used. For example, retardation plates for prevention of coloring, viewing-angle expansion films for improving viewing angle of liquid crystal displays, and furthermore, brightness enhancement films for increasing contrast of displays etc. are used. These films are generically named and called optical films.
In case of adhesion of the optical films to liquid crystal cells, pressure sensitive adhesives are usually used. Moreover, in adhesion between optical films and liquid crystal cells, and between optical films, each element usually is attached using pressure sensitive adhesives in order to reduce loss of light.
In these optical films, in order to prevent occurrence of damage and contamination to a surface of the optical film in transportation or manufacturing process until it is sent to consumers, surface protective films are usually attached on a surface thereof. The surface protective film is attached from a stage in which the optical film is in a state of single substance, and in some case it is peeled after being attached onto an LCD etc., and furthermore in other cases it is attached again after peeled to a same or another surface protective film. And there have been problems that static electricity generated in case of peeling of the surface protective film may destroy circuits, such as in LCD panels.
Although ITO treatment is usually performed on a cell substrate of one side of liquid crystal cell in case of LCD especially driven by IPS mode, antistatic treatment is not performed to an opposite side. For this reason, when a surface protective film is further removed from an optical film attached on a side without ITO treatment, separation electrification is generated, causing to occurrence of disorder of pictures. There are problems, also in a stage of completed panel finished products, that electrification is generated by wiping of pollution on a surface by cloths etc. in optical films of viewing side (upper side), or by contact with a diffusion film in the optical film of incidence side (lower side), resulting in disorder of pictures. Also in case of LCD driven by VA mode, when a cell substrate without ITO treatment given is used on one side of a liquid crystal cell, same problems occur.
In order to solve the above-mentioned problems, disclosed are a polarizing plate with an antistatic film having an antistatic film currently formed on a surface thereof (Japanese Patent Laid-Open No. 2-73307 official report), and a polarizing plate having a transparent conductive layer(s) prepared on one side or both sides thereof (Japanese Patent Laid-Open No. 4-124601 official report).